Dear BITOG Members: We wanted to let you know that we are changing our TBN testing process slightly. We have always run a modified version of ASTM D-4739, but our machine was calibrated using standards that more closely matched to ASTM D-2896. We are now moving to standards that are more closely aligned with D-4739 and the only difference we have noticed is a slight drop in virgin oil TBN readings. The used oil TBN readings are not expected to change much at all, but virgin oils will tend to read a little lower. ASTM D-2896 is a method used by oil companies to provide TBN readings for their virgin product. It uses stronger acids than ASTM D-4739, so it tends to give higher readings. Since we mostly see used oil, we picked ASTM D-4739 as our method of choice, and this change in standards should give us more consistent readings. (ASTM methods are generally available at your local library at no change if you want to see the actual method.)

Because BITOG members tend to watch virgin TBN readings closely, we wanted to let you know about this change. And to help smooth out the transition, we will also be willing to run any samples you wish under both methods so you can see for yourself what type of differences occur. If you want to take advantage of this, just send in your sample and ask for both TBN methods on the oil information slip. Feel free to contact me with any questions you might have.